Embodiments of the present invention generally relate to wind turbines and more particularly relate to a system and method for controlling wind turbines in wind farms.
Wind turbines are used to generate electrical power from wind energy. Multiple wind turbines may be coupled together to form a wind farm, and multiple wind farms may be coupled to a power grid. The wind farms are required to provide a committed output power to the power grid. However, due to constant fluctuations in wind speed and in load coupled to the power grid, a difference may occur between the power provided by the wind farm to the power grid and the committed output power. The difference leads to variations in a frequency at the power grid and may require additional wind farm resources for frequency regulation.
In order to overcome the variations in the frequency, wind farms use various frequency response techniques. One type of primary frequency response method includes operating wind turbines in respective wind farms in a curtailed mode during normal operational modes and operating the same wind turbines to provide additional power when frequency decreases or curtail the wind turbines further when frequency increases. However, operating the wind turbines in a curtailed mode during normal operational modes results in revenue losses.
In some situations, the above type of primary frequency response technique is insufficient to maintain a precise control of the frequency in the power grid and a second frequency response technique is employed to precisely control the frequency in the power grid. One example of a secondary frequency response is an automatic generation control embodiment including a centralized wind farm battery that provides additional power to the power grid to maintain the frequency. Such secondary systems lead to additional costs of the wind farm.
It would be desirable for wind farms to have an improved and more cost effective system and method to address frequency variations.